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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Environmental geology 27 (1996), S. 155-163 
    ISSN: 1432-0495
    Schlagwort(e): Radiometric dates ; Heavy metals ; Anthropogenic input ; Cauvery basin ; Remobilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie
    Notizen: Abstract Eleven cores were collected from the Cauvery basin. Radiometric dates were used to determine modern sediment accumulation rates. Sediment accumulation rates ranged from 0.4 to 4 mm yr−. Heavy metal concentration decreases with the increase of depth. The heavy metal concentrations at certain depths are attributed to the irregular input of metals and their remobilization. Heavy metal accumulations have been computed using sediment accumulation rates, and accumulation rates show an additional anthropogenic input of metals and sediments in the recent past. Factor analysis and correlation analysis show the diverse source and accumulation mechanism influencing the metal distribution in the basin.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Environmental geology 17 (1991), S. 117-126 
    ISSN: 1432-0495
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie
    Notizen: Abstract Suspended and bed sediments collected from the entire region of the Godavari River basin were analyzed for Fe, Mn, Cr, Cu, Ni, and Zn. There are pronounced temporal and spatial variations in the heavy metal distributions. The concentrations of heavy metals in the suspended sediments are significantly higher than the bed sediments. Throughout the basin heavy metals are enriched in the finer fractions (〈2 µm) of the bed sediments. The average heavymetal composition of the sediments is higher when compared to the average Indian river sediments. Heavy-metal concentration in the two shallow cores collected shows, to some extent, the influence of urbanization. When compared to the other tropical Indian rivers such as the Krishna, the Godavari appears to be a significant contributor of heavy metals to the Bay of Bengal. Considering the enormous sediment load of the Godavari River—170 million tons/yr, the heavy metal fluxes to the Bay of Bengal is very significant. Except for the Pranhita, other tributaries of the Godavari do not contribute significant loads of heavy metals. All the metals show high correlation among themselves and the correlation is more pronounced in suspended sediments than in the bed sediments. The heavy-metal distribution, fractionation, and its relationship with total suspended sediments and depth in various parts of the basin are discussed in detail.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1432-0495
    Schlagwort(e): Key words Mangrove ; Geochemistry ; Biological productivity ; Anthropogenic impacts ; Heavy metal sink
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie
    Notizen: Abstract  Spatial and temporal geochemical variations of various parameters in the water and sediment of a relatively small mangrove situated on the southeast coast of India were examined in detail for the first time. The water quality generally reflects the impact of seawater and the Vellar estuary (mixing effect) aided by evaporation and in situ biological productivity. The depletion and fluctuation of dissolved silica are controlled by biological processes. Nitrate and phosphate are contributed by fertilizer input from adjoining agriculture fields. Total suspended matter (TSM) shows an erratic range and trend due to deforestation and resuspension processes. Sand and silt constitute 70–90% of the sediments. Statistical analysis of the sediments shows the prevalence of a moderately high-energy environment with very effective winnowing activity. Organic matter content is higher in the mangrove sediments in comparison to adjacent estuaries. Water and sediment show fluctuations in their chemical concentration, but no specific trends could be identified. Heavy metals are also enriched in the mangrove sediments, indicating their unique chemical behavior and the existence of trapping mechanisms. Factor analysis and correlation analysis of water and sediments show the complexity of the system and the multitude of contributing sources. The core sediment chemistry suggests the depletion of metal input due to the damming of the detrital inputs. The Pichavaram mangrove seems to be relatively unpolluted, since the anthropogenic signal observed is small and acts as a sink for heavy metals contributed from a multitude of sources without an adverse effect.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 1573-5117
    Schlagwort(e): Rare earth elements ; estuarine sediments ; east coast of India ; heavy metals
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Bed sediment samples collected from the Hoogly, Godavari, Krishna and Cauvery estuaries on the east coast of India were analyzed for rare earth elements (REEs), mainly lanthanides (La–Lu), Y, a number of metals (V, Cr, Co, Ni, Zn, Ag, Cd and Pb), using Thermal Ionization Mass Spectrometry. Continental weathering plays an important role in the distribution of REEs and metals. However, metals showed wide variation in concentration among estuaries, mainly due to varying salinity, which controls complex estuarine processes, and partly to anthropogenic inputs. Factor analysis of elemental data identified two major groups of elements: (i) LREEs, HREEs, Cd, Pb and Ag, revealing an association with detritals brought in by the rivers; and (ii) V, Cr , Co, Ni and Zn, indicating complex estuarine processes and human input. LREEs are more enriched than HREEs (LREE/HREE ratio varied between 12 and 40) reflecting silicate weathering of crustal materials, and a resultant increase in LREEs in detritals. We conclude that the estuarine system constitutes 70% of LREEs and 30% of HREE flux to the Bay of Bengal.
    Materialart: Digitale Medien
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